Late last year, Dr. William Hagan, acting director of the Department of Homeland Security’s (DHS) Domestic Nuclear Detection Office (DNDO) testified at a hearing of the Subcommittee on Investigations and Oversight that the demand for helium-3, an essential component in neutron detecting radiation monitors, outstripped supply by a ratio of ten to one and the stockpile was disappearing. As a result, a White House task force halted the use of helium-3 for use in radiation detection monitors.[1]

[1]“The Science of Security Part II: Technical Problems Continue to Hinder Advanced Radiation Monitors,” Committee on Science and Technology, Subcommittee on Investigations and Oversight, U.S. House of Representatives, Nov. 17, 2009.